Study on Practicability of A Chair-side 3D Cephalometric System

Research Project

Project/Area Number	11557167
Research Category	Grant-in-Aid for Scientific Research (B).
Allocation Type	Single-year Grants
Section	展開研究
Research Field	矯正・小児・社会系歯学
Research Institution	Tsurumi University
Principal Investigator	NAGASAKA Satoshi Tsurumi University School of Dental Medicine, Orthodontics Department, Assistant, 歯学部, 助手 (60277952)
Co-Investigator(Kenkyū-buntansha)	KUWAHARA Yosuke Tsurumi University School of Dental Medicine, Orthodontics Department, Professor, 歯学部, 教授 (30064348)
Project Period (FY)	1999 – 2000
Project Status	Completed (Fiscal Year 2000)
Budget Amount *help	¥11,700,000 (Direct Cost: ¥11,700,000) Fiscal Year 2000: ¥4,300,000 (Direct Cost: ¥4,300,000) Fiscal Year 1999: ¥7,400,000 (Direct Cost: ¥7,400,000)
Keywords	Non-irradiation / Chair-side / Cephalometry / 3D digitizer / Cnotact-method / Head-fixation / 計測誤差 / 受け入れ検査 / 頭部固定 / 精度 / 3Ddigitizer / 日本工業規格 / 国際標準化機構
Research Abstract	In pursuit of cephalometry featured with non-irradiation to patients, readiness of data and compactness and simplicity of the system, we developed a portable 3-D computer-aided contactmethod cephalometric system for dental chair-side use. Introducing its basic concepts, the feasibility of its clinical use is seeked based on comparison of the measurements obtained by the new system with those by the conventional X-ray cephalometry on a human dry skull as well as three living human subjects. Based on the three-plane system theory of Simon, a software was programmed so that 3D coordinates of craniofacial landmarks digitized with a contact-method 3D digiitzer, MicroScribe-3D^<【○!R】> can be mathematically projected onto any of the three predetermined reference planes (the median sagittal plane, the Frankfort horizontal plane, the orbital plane) in order to obtain measurements comparable to those obtained by X-ray cephalometry. For chairside digitization, the subjects were told to lie on their back on the reclined dental unit with their head fastened to the headrest with a cloth band for head fixation. The measurement results were examined from both statistical and clinical viewpoints, compared with the corresponding results from X-ray cephalometry. While part of the tooth-related measurements seemed to need further consideration and examination on the data, skeletal measurments on the whole seemed to be clinically valid. It was confirmed that with a little more refinement the system which itself is already practicable can be clinically applicable at least to summary use in cephalometric diagnosis. Part of the present study was presented at the 100^<th> annual session of the American Association of Orthodonitsts, Chicago, April 28-May 3, 2000 as well as at the 76^<th> Congress of the European Orthodontic Society, Crete, Greece, , June 2-6, 2000. Part of the present study was also published in Tsurumi University Dental, Journal, January 2001, Vol.27 No.1.